Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cc6eddcd authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files

media: v4l2-dev: lock req_queue_mutex 



We need to serialize streamon/off with queueing new requests.
These ioctls may trigger the cancellation of a streaming
operation, and that should not be mixed with queuing a new
request at the same time.

Finally close() needs this lock since that too can trigger the
cancellation of a streaming operation.

We take the req_queue_mutex here before any other locks since
it is a very high-level lock.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 93a9d900

drivers/media/v4l2-core/v4l2-dev.c

+16 −2
Original line number Diff line number Diff line
@@ -444,8 +444,22 @@ static int v4l2_release(struct inode *inode, struct file *filp) 
	struct video_device *vdev = video_devdata(filp);

	int ret = 0;



	if (vdev->fops->release)

	/*

	 * We need to serialize the release() with queueing new requests.

	 * The release() may trigger the cancellation of a streaming

	 * operation, and that should not be mixed with queueing a new

	 * request at the same time.

	 */

	if (vdev->fops->release) {

		if (v4l2_device_supports_requests(vdev->v4l2_dev)) {

			mutex_lock(&vdev->v4l2_dev->mdev->req_queue_mutex);

			ret = vdev->fops->release(filp);

			mutex_unlock(&vdev->v4l2_dev->mdev->req_queue_mutex);

		} else {

			ret = vdev->fops->release(filp);

		}

	}



	if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)

		dprintk("%s: release\n",

			video_device_node_name(vdev));

drivers/media/v4l2-core/v4l2-ioctl.c

+21 −1
Original line number Diff line number Diff line
@@ -2780,6 +2780,7 @@ static long __video_do_ioctl(struct file *file, 
		unsigned int cmd, void *arg)

{

	struct video_device *vfd = video_devdata(file);

	struct mutex *req_queue_lock = NULL;

	struct mutex *lock; /* ioctl serialization mutex */

	const struct v4l2_ioctl_ops *ops = vfd->ioctl_ops;

	bool write_only = false;
@@ -2799,10 +2800,27 @@ static long __video_do_ioctl(struct file *file, 
	if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags))

		vfh = file->private_data;



	/*

	 * We need to serialize streamon/off with queueing new requests.

	 * These ioctls may trigger the cancellation of a streaming

	 * operation, and that should not be mixed with queueing a new

	 * request at the same time.

	 */

	if (v4l2_device_supports_requests(vfd->v4l2_dev) &&

	    (cmd == VIDIOC_STREAMON || cmd == VIDIOC_STREAMOFF)) {

		req_queue_lock = &vfd->v4l2_dev->mdev->req_queue_mutex;



		if (mutex_lock_interruptible(req_queue_lock))

			return -ERESTARTSYS;

	}



	lock = v4l2_ioctl_get_lock(vfd, vfh, cmd, arg);



	if (lock && mutex_lock_interruptible(lock))

	if (lock && mutex_lock_interruptible(lock)) {

		if (req_queue_lock)

			mutex_unlock(req_queue_lock);

		return -ERESTARTSYS;

	}



	if (!video_is_registered(vfd)) {

		ret = -ENODEV;
@@ -2861,6 +2879,8 @@ static long __video_do_ioctl(struct file *file, 
unlock:

	if (lock)

		mutex_unlock(lock);

	if (req_queue_lock)

		mutex_unlock(req_queue_lock);

	return ret;

}